Chen Xuan habitually turned the pen, and then said, "Senior sister, in fact, you can change your thinking in another way for this question, and you don't need to be too entangled. ”

"But I don't know where to start, let alone what the topic is about." Lu Yansheng's cheeks were flushed, and he was really embarrassed. The senior sister in the third year of high school, it is a very embarrassing thing to let the junior teach mathematics.

What's more, her math is still so bad that even the problem of the properties of a simple quadratic function is a little difficult.

"Well, let's do it, I'll write out the thinking process of this question first, and you slowly recall that the teacher should have talked about this kind of similar topic in class." Chen Xuan smiled mildly and said.

"Okay." Lu Yansheng lowered his head slightly, and his cheeks were as hot as a big stove. She really wanted to say to Chen Xuan, junior brother, don't be kidding, it's just that when you were in class, you didn't listen to the teacher's lecture at all, so it would fall to such a point.

is no longer hypocritical, Chen Xuan grabbed the pen without saying a word, and neatly wrote down the process of solving the problem on the scratch paper, while writing, he explained gently, "This question is related to the previous topic, you see, from (1) gets: g(x)=x²-2x+1, so f(x)=x²-2|x|+1 is an even function." It's a simple parity problem, senior sister should understand, right?"

Lu Yansheng frowned lightly and nodded thoughtfully, she had still heard of the problem of oddity and evenness, so she said confidently, "Don't worry, senior sister, I can still do math." ”

"......" Chen Xuan was silent, he had seen the cheekiness of this senior sister. However, he didn't say anything, on the contrary, he also felt that this senior sister had a very cheerful personality.

"And what about the next steps?" Lu Yansheng completely forgot what he had just said that mathematics was okay, and asked again suspiciously.

"The rest of the process, in fact, is not very difficult." Chen Xuan silently added a sentence in his heart, it is estimated that it is difficult for you to understand, senior sister.

Lu Yansheng didn't have the ability to read minds, so naturally she wouldn't know Chen Xuan's thoughts, she smiled happily and said excitedly, "Then junior brother, tell me quickly." ”

"Hmm." Chen Xuan nodded, then silently wrote it down on the scratch paper, and explained, "According to the parity above, we can deduce from it that the inequality f(log2k)>f(32) can be reduced to |log2k|>32"

"Junior brother, can you talk in layman's terms, I don't understand the meaning of this." Lu Yansheng thought carefully about the idea of this question, but she really couldn't understand why the first step was quite simple, and the next step directly skipped so many steps, so she couldn't understand it.

"......" Chen Xuan is tired, it is a simple simplification and equal substitution, it is very difficult? He finally realized the despair of Mu Wanqing and Ye Lingxuan for mathematics.

"Senior sister, can I take the liberty of asking you a question?" Chen Xuan smiled gently and said lightly.

"Hey, there is something that the junior brother doesn't understand?" Lu Yansheng seemed surprised that Chen Xuan actually had a question to ask her, which made her very proud, she patted her chest and said confidently, "Don't worry, junior brother, as long as it is a problem that you can come up with, there is nothing I can't solve." ”

Looking at the turbulent scene, Chen Xuan shook his head helplessly, sure enough, this is inversely proportional. He asked lightly, "Senior sister, have you ever learned simplification?" ”

"Brother, don't you know how to simplify such a simple math problem?" Lu Yansheng covered her small mouth and looked at Chen Xuan with a shocked expression, she was really shocked that this junior of a math bully could not simplify.

"......" Chen Xuan's face turned blue, and he didn't know what to say for a while. Fortunately, his patience was very good, calmed his mood, and said with a faint smile, "Senior sister, I mean, this question is just a simple simplification and equal substitution, and it won't be difficult in fact." ”

"Ah, really? But why can't I understand something? Lu Yansheng looked at these strange symbols strangely, and really couldn't understand why these symbols were equal.

"Senior sister, do you want to see if this question has the same symbols, and it is in the same direction?" Chen Xuan was patient and explained slowly.

"Hey, yes, can the same symbol be the same?" Lu Yansheng looked at Chen Xuan suspiciously, wanting to hear his explanation.

Well, that's okay, but that's not all the same thing. However, in the early stage, you can get closer to this idea, after all, mathematics is not a constant subject, and it is constantly evolving with the times. Chen Xuan thought about it and said lightly.

"It's amazing, junior, I didn't expect your understanding of mathematics to be so profound." Lu Yansheng said that he admired Chen Xuan very much. also silently cheer yourself up in your heart, you can too!

"Let's not talk about these first, you see that the topic is here, in fact, it is over, but because the topic is for us to find the value range of the real number k, this has to be applied to the knowledge points of the first year of high school." Chen Xuan clicked on the steps to solve the problem and said.

"Well, don't worry, junior, I can understand." Lu Yansheng said confidently.

"......" Chen Xuan looked at the confident Lu Yansheng, he really didn't want to hit him, he was patient, and continued to explain, "The last step is to simplify it into this appearance, and solve it: k∈(0,√24)∪(2√2,+∞)"

"Oh, I kind of get it." Lu Yansheng waved his pink fist with some excitement and said happily.

"Ahem!" A heavy cough came from the row in front of the two.

After realizing the sound of the two of them talking again, disturbing the others, Lu Yansheng's cheeks flushed, he spit out his fragrant tongue, and after thanking Chen Xuan, he happily returned to his place with the exercise book and scratch paper.

Chen Xuan looked at Lu Yansheng who was far away, and said silently in his heart, "Senior sister, you think too much, in fact, you don't understand this question at all, you just roughly know your thinking, and you will find out later, you still don't know where to start." ”

"Forget it, let's continue to read books." Chen Xuan shook his head, and then entered the state again, completely leaving this matter behind, just as a small episode of brushing books in the library.

By 8:40 in the morning, a copy of "Analysis of High School Knowledge Base" was thoroughly eaten by himself, and it can be said that except for some real top problems, high school mathematics knowledge is basically no longer able to stop him.

Chen Xuan put this book back with satisfaction, he is now a primary school bully, but he doesn't have to worry about whether his identity will be exposed.

After looking at the clock on the wall, Chen Xuan walked back to the classroom slowly.

In Feng Zhiqi Middle School, generally speaking, reading starts at 7:40 and ends at 8:20. Then, the first class starts and is not finished until 10:10 a.m.

Now, it's only 8:45, and the first class is actually only halfway through. The first class is a self-study class, which is a very exciting course for students in the first year of high school, no less than computer classes and physical education classes.

After all, the self-study class teacher basically doesn't come over, and this is the time for them to play.